Electricity: circuit makers and breakers – Toggle mechanisms
Patent
1997-02-05
1998-04-28
Walczak, David J.
Electricity: circuit makers and breakers
Toggle mechanisms
200400, H01H 2300
Patent
active
057433852
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a drive device of a power switch having a switch shaft in common for several poles, the switch shaft being able to be acted upon in the switching-on sense by means of a spring energy store via toggle levers on one hand, and on the other hand by pole-side breaking forces in the switching-off sense. A mechanical locking device is provided as protection against a rebound of the switch shaft out of its final position upon switching off.
BACKGROUND OF THE INVENTION
A drive device of this type is disclosed in U.S. Pat. No. 4,468,533. In that case, the locking device comprises a hooklike lever whose hooklike region arrives near a fixed bolt upon switching off and engages over it. The hooklike lever, supported on a lever located on the switch shaft, is acted upon by a resetting spring which draws the hooklike lever back again and again establishes the normal movability of the switch shaft.
The bounce of the switch shaft upon reaching the off position is dependent on a number of different factors. Of importance in this connection are not only the mechanical properties of the moved parts, i.e., their mass, their elastic deformation caused by the forces occurring and their velocity, but also the current that is to be interrupted in each case by the switching contacts of the power switch and from which an electrodynamic effect emanates upon the moved parts. That is why it causes considerable difficulty to design the mentioned locking device in such a way that it controls the bounce within the entire power range of a power switch, i.e., from normal operating currents to the greatest short-circuit currents. For example, a locking device of the type indicated can be effective given a certain switching current, however neither in the case of a lower nor in the case of a higher current.
OBJECTS AND SUMMARY OF THE INVENTION
An object of this invention is to design a locking device of the type named at the outset in such a way that it is effective regardless of the strength of the switching operation.
This objective is achieved according to the invention in that at least one retainer is secured on the switch shaft and that the clamp is arranged in a manner that it is pivotable about a fixed bearing, the retainer having a working surface for acting upon the clamp in the sense of a grasping of the retainer. This arrangement can be utilized regardless of the levers that are located on the switch shaft and by means of which the driving forces are introduced into the switch shaft and passed on from it. Therefore the locking device formed by the clamp must be mounted at a suitable location and, given suitable dimensioning, is also usable repeatedly if necessary.
In one advantageous refinement of the invention, the clamp can be designed with an aperture open on one side having a curved arcuate outer wall adapted to the retainer and an overlapping between the retainer and the clamp can be dimensioned to be considerably larger than is necessary to block the switch shaft from turning back. In this manner the operating range of the locking device is considerably enlarged because the clamp can engage for a variable distance over the retainer without a limit stop in a final position which could impair the effectiveness of the device.
The aperture of the clamp can have a curved end wall, while the retainer has a straight end border. A beneficial consequence of this structural arrangement is that a reflection of the clamp due to bounce does not happen even when the overlapping between the retainer and the clamp is completely passed through and the clamp bumps with the end face of its aperture against the end of the retainer.
As a further advantageous measure for expanding the operating range of the locking device, two identical arrangements composed of retainer and clamp can be arranged at the switch shaft and the resetting springs of the two clamps can be designed with different strengths.
It is beneficial for the effectiveness of the locking device described if the retainer is suppor
REFERENCES:
patent: 4468553 (1984-08-01), Kodera et al.
patent: 5226528 (1993-07-01), Schaffer et al.
patent: 5310971 (1994-05-01), Vial et al.
patent: 5486667 (1996-01-01), Castonguay et al.
patent: 5571255 (1996-11-01), Baginski et al.
Siemens Aktiengesellschaft
Walczak David J.
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